How to Make It
Preheat the oven to 350°. Spread the walnuts in a pie plate and toast for about 8 minutes, until lightly golden and fragrant. Let cool completely, then coarsely chop.
In a small bowl, combine the shallot with the sherry vinegar. Whisk in both oils and season with salt and pepper.
In a large bowl, toss the toasted walnuts, celery, dates and pecorino. Add the dressing and toss. Serve at once.